What are the requirements for using a light meter?
1. Visual illuminance meter: inconvenient to use, not very accurate, rarely used
2. Photoelectric illuminance meter: Commonly used selenium photovoltaic illuminance meter and silicon photovoltaic illuminance meter
The composition and usage requirements of photocell illuminance meter:
1. Composition: microammeter, shift knob, zero point adjustment, terminal, photocell, V(λ) correction filter, etc.
Commonly used selenium (Se) photovoltaic cells or silicon (Si) photovoltaic cells illuminance meters, also known as lux meters
2. Usage requirements:
The illuminance meter probe is made of glass, which is easy to break and break. When used at the same time, the waterproof effect is very poor.
① Photovoltaic cells should use selenium (Se) photovoltaic cells or silicon (Si) photovoltaic cells with good linearity; they can still maintain good stability and have high sensitivity after long-term operation; when the E is high, use photovoltaic cells with high internal resistance, which have low sensitivity and good linearity. , not easily damaged by strong light exposure
② There is a V (λ) correction filter inside, which is suitable for illumination of light sources with different color temperatures and has small errors.
③Add a cosine angle compensator (opalescent glass or white plastic) in front of the photovoltaic cell. The reason is that when the incident angle is large, the photovoltaic cell deviates from the cosine law.
④The illuminance meter should work at room temperature or close to room temperature (photocell drift changes with temperature changes)
